The present application relates generally to charges that include a thermite core and the use thereof in well perforation and downhole fracing.
Perforating or fracing devices are often used to complete oil and natural gas wells. Typically, these devices having an array of charges are lowered downhole into a well having a casing. When the device is at the correct depth in the well, the charges are fired, sending shaped charge jets outward through the side of the device, through any fluid between the device and the well casing, through the well casing, and finally into the oil-bearing or natural-gas bearing rock. The resulting holes in the well casing allow oil or natural gas to flow into the well and to the surface. After the charges have been fired, the remains of the device may then be withdrawn from the well or left in the well. Perforating device technology is disclosed in the art. (See, e.g., U.S. Published Application Nos. 2009/0114382; 2009/0151949; and 2006/0070739; and U.S. Pat. Nos. 6,349,649; and 6,386,109, which are incorporated by reference in their entireties).
A charge for a perforating or fracing device typically includes an energy source within its core, some mechanism to ignite the energy source, and optionally a case and optionally a liner. Energy sources typically include explosive materials, and new, non-explosive energy sources for charges are desirable. Here, thermite material is disclosed as a suitable material for charges, where after ignition, thermite material typically exhibits deflagration rather than explosion. While thermite material has been used in the art for forming liners for charges, liners typically represent a small percentage of the total weight of a charge (i.e., less than 5% of the total weight of the charge). As such, material of a charge liner typically does not provide an energy source for the charge.